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B M F

Astro Hog Refit and Modification

A good while ago I bought an Astro Hog from Bill Wood which was very nicely built and fitted with an ASP 61 two stroke engine. It flew quite nicely on this but then I decided that it would sound better with a 4 stroke. The conversion wasn’t all that well done and rather messed up the front of the model but it did still fly and sound more like the vintage model that it is.

Other projects and a lot of wasted effort elsewhere meant that the Astro Hog hasn’t had much use during the last year or so but looking at it in the corner of the workshop the other day I thought I may try and smarten it up a bit. In the other corner of the attic I have the last remaining items left over from or sadly departed friend, Jon Rowe, comprising an almost completed pair of floats. Having completely soaked my Lake Mister seaplane, (Joe Priestnall kit) which at first looked recoverable, I found it to be more warped than a dog’s hind leg and probably unflyable. That airframe has now been stripped and the remnants consigned to the bin.

Back to Jon’s floats, the built in captive nuts are threaded for 6Ba bolts; has anyone tried to source Ba nuts and bolts recently? Danlet, give them their due did search through their old stock and came up with enough for the job in hand at 25 pence per one inch bolt (Plus VAT) Ouch! I just need now some one inch x one eighth inch aluminium flat bar to join everything together. This also appears to be a commodity that is drifting towards extinction though I have found a supplier in Wetherby. It looks as though it will be cheaper to take Julie out for a day in Wetherby and collect it than to pay the postage on the amount I want.

Even though the Astro Hog was designed around a 40 size engine it is a big enough model for the sixties that it has already been flown on. With the fairly heavy floats fitted I think a good bit more grunt up front may be required to drag it around, particularly if, as I hope to do, fly it from wet grass so I hope to fit an SC 91. I bought this engine brand new and never run from John Torr so long ago that the oil the Chinese put in it to “preserve” it had solidified to such an extent the rear bearing had seized up solid. A few instructional videos later and I now have an SC 90 in all its component parts; just hope it all goes together when the new bearings arrive.

Continuing the Jon Rowe floats rebuild: -

After a lot of varnish one float is now covered and the other is waiting for a visit to the model shop for ANOTHER bottle of expensive water-proofer. At least I pass Crossgates on the way to Wetherby to collect the equally expensive aluminium bar that will be used to turn the floats into on, detachable I hope, unit.

A bit of a setback has occurred with the new bearings for the SC 91 they arrived promptly but were both the wrong size. I think my engine is an even earlier model than I thought. Sent the new and old bearings back to ModelFixings UK in the hope they can match them. Not sure what I will do if they can’t.

New Bearings arrived today and now fit beautifully after cooking the crankcase in Julie’s oven for 20 minutes.

Floats are now joined together but now I need to know how to bend aluminium to make the struts up to the fuselage. So far I have broken two 3.5 mm drill bits making this.

Continuing the saga of fitting floats to my Astro Hog I realised I needed to bend the aluminium bar and didn’t fancy either heating it in case I melted it or putting it in a vice and hitting it with a big hammer. Searching the internet for ways to bend metal I am still amazed there are about one million ways to do this. One guy had a video of how he bent just the same size of flat bar as I am using so to a very rough extent; and I am sure John Mosley will agree with me it is very rough, I made a bender.


Very basically it is one metre of steel angle iron cut into five 200mm pieces and bolted together around two 75mm hinges. Two pieces are hinged back to back; another piece is bolted on top of one side with wing nuts to act as a clamp for the workpiece. The remaining two pieces are the levers that hold the bender in a vice and the other, which could do with being a bit longer, is the handle with which to apply the bending force.

It all looks a bit like something that Wilf Lunn may have invented but to my surprise it does actually work quite well.

Sorry about the multicoloured carpet and cluttered background but everything is nicely amphibous now and I dont have to remove the wheels. Next I need to build (or buy) a new cowl and I am almost ther
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© Feel free to copy anything you want. Alec Barber.